Chemical abscission of fruits at low application rates

ABSTRACT

The harvesting of fruit, in particular olives and citrus fruit, is aided by inducing abscission by applying to fruit-bearing parts of the plant certain imidazolinone or sulfonylurea compounds. The compounds are applied in aqueous solution or in extremely low concentration in amounts ranging from 15 to 200 ppm, preferably from 20 to 70 ppm, by spraying to the point of incipient run-off.

This application has been filed under 35 USC 371 as the national stageof international application PCT/US97/07684, filed Apr. 29, 1997. Thisapplication claims benefit of Provisional Appl. 60/016456 filed Apr. 29,1996 and Provisional Appl. 60/028823 filed Oct. 17, 1996.

The ability of plants to slough off organs by an active separation ofcells is distinctive to higher green plants. Plant physiologistsdescribe this process as abscission. This invention relates to the useof certain chemical compounds as agents to promote the abscission offruits, and to compositions comprising said compounds.

The harvesting of fruit crops has traditionally been accomplished bymanual labor. However, in recent years, the shortage and expense ofmanual labor has prompted the development of other means for picking andharvesting fruit crops. To this end, a wide variety of mechanicaldevices has been developed, each of which operate in accordance with adifferent principle in order to remove fruit from trees or plants. Forexample, one device utilizes giant fans for generating strong air blaststo blow the fruit from the trees. Another device includes a series ofnotched or toothed arms which operate by combing the tree limbs therebyraking the fruit from the trees. Finally, mechanical shakers have beendeveloped having an arm or boom which is connected to either a branch orthe trunk of the tree and operates by violently shaking the tree inorder to shake the fruit loose. However, none of these devices has beenentirely successful in many crops. If the fruit is firmly attached tothe tree, strong air blasts or mechanical shaking cause the fruit tostrike spurs, branches and other fruit thereby bruising and damaging thefruit. Since the force necessary to remove firmly-attached fruit isusually that force necessary to tear the rind, many fruits suffer openwounds and tearing when these mechanical devices, as well as the notchedarms, are used. The result is poor quality fruit since there is usuallya considerable time lapse between the time of harvesting and the time offinal use within which the fruit is subject to decay where wounds andbruises appear. In addition, the force generated by these mechanicaldevices causes the removal of twigs, leaves and branches which arecarried with the fruit to the processing plant. Such extraneous mattermust be removed manually in order to avoid damage to the fruitprocessing machinery, which is a time-consuming and expensive operation.Finally, it has been observed that long periods of shaking by mechanicalshakers result in bark damage and disturbance to the root system, whichcan easily result in long-term plant destruction.

It has now been found that by first treating the fruit-bearing plantswith an appropriate chemical abscission agent, the fruits are induced toabscise with either little or no mechanical aid.

Chemicals used to assist in loosening the fruit for the harvestingoperation are sometimes called, in general terms, harvesting aidchemicals or fruit loosening chemicals. If the amount of force needed toseparate a fruit from the rest of the plant can be reduced through theuse of chemical, this would be a significant contribution to agricultureand would be useful to farmers and growers. Such a chemical would allowpickers to pick the fruit easily and more quickly. In the case wheremechanical harvesters are used, the amount of force which would have tobe applied by the mechanical harvester could be reduced. More fruit pertree (per vine, or unit or row) could be harvested more easily anduniformly. Less damage to the fruit itself and to the rest of the plantwould result if a chemical loosening agent effectively reduced therequired harvest force. The quality of the fruit would increase becauseof less damage and possibly the yield per tree (per hectare, or perother unit of measure) would increase because of a more uniform andcomplete harvest.

This invention relates to the use of certain chemicals which have apositive and beneficial effect on the abscission process. Theyfacilitate and make the harvesting of crops easier. To harvest fruit,whether it is done by hand or mechanically, a given amount of force(energy) must be applied by hand or mechanically to the fruit, orportion of the plant to be harvested, in order to force it to abscise,or come loose from the rest of the plant. Both manual and mechanicalharvesting methods can be more commercially successful where effectiveabscission agents are used, since potential damage to the crop can besignificantly reduced. Their use helps to keep the unit cost ofproduction down to a reasonable level. Where hand labor is still used inharvesting crops, any practice that can help to increase theproductivity of a person per unit of time would be an importantagricultural contribution.

This invention is concerned with chemical compounds useful in promotingthe abscission of all types of fruits. From a practical and economicstandpoint, however, this invention is more concerned with theharvesting of fruit derived from fruit-bearing trees and vines havingeconomic value, such as citrus fruits (particularly, oranges, lemons,limes and grapefruit), cherries, and olives and reference will be madeto this type of fruit for illustrative purposes although it is to beunderstood that the invention is not intended to be limited thereby.

The precise biochemical mechanism of abscission is not of primeimportance for the understanding of this invention, but the compositionsdisclosed herein enter into the biochemical reactions involved in theabscission cycle in a manner to induce or hasten the abscission cycle ofmature or near-mature fruit. It is the purpose of this invention todisclose compositions and methods for chemically bringing about orinducing the abscission of fruit from fruit-bearing plants at the stageof fruit development just prior to full ripeness such that the fruit maybe economically harvested for commercial use. Therefore, the term"abscission" as used herein refers to the separation of fruit from itstree at the stage of development at or just prior to fruit maturity.

The compounds used in the methods of this invention help to loosen thefruit which is to be harvested while, at the same time, they do notsignificantly damage the rest of the plant.

Various abscission agents have already been suggested, and in some casesused to a limited extent, but these are frequently unsatisfactory onaccount of undesirable side-effects. An example of these iscycloheximide (Cooper, U.S. Pat. No. 3,663,199) which, in spite of anexcellent abscission action in the case of some citrus fruits, is notadapted to use on the "Valencia" orange, as it has a great disadvantagein that it severely damages blossoms and unripe fruit (both of which aresometimes found on the "Valencia" at harvest time), has a pronounceddefoliating action, and gives rise to considerable scarring on ripefruit. Other examples are glyoxime (Wilcox, U.S. Pat. No. 4,052,194) and5-chloro-3-methyl-4-nitropyrazole (Crovetti, U.S. Pat. No. 3,869,274),which can also be used on "Valencia" oranges if the fruit is processedwithin about three days.

Although abscission agents known in the prior art have been satisfactoryfor some purposes, it would nevertheless be desirable to developabscission agents which can be used on a variety of fruits and at verylow application rates. The advantages in applying chemical compounds atrates lower than heretofore possible are obvious; these advantagesinclude lower costs, less likelihood of adverse environmental effects,little or no damage to the tree, etc.

In recent years, there have been developed a number of selectiveherbicidal chemicals which are said to be useable at relatively lowapplication rates. These include two broad classes of compounds whichwill be referred to herein as the "sulfonylureas" and the"imidazolinones". There are numerous patents disclosing a wide varietyof sulfonylurea and imidazolinone compounds, including those mentionedspecifically below. The inventors have found that certain specificcompounds disclosed in these patents are useable as fruit abscissionagents and are particularly advantageous in that they can be employed inconcentrations lower than the concentrations heretofore required inabscission compositions. In general, these patents indicate that thesubject compounds are useful as herbicides and some patents alsodescribe the compounds in general terms as plant growth regulants. Insome of these patents, there is a general reference to possible utilityof some of the subject compounds as abscission agents, but no detailsare given as to specific compounds, methods of use, concentrations,crops, or any other information which would enable a person skilled inthe art to use the subject compounds as abscission agents for fruit. InWillms, U.S. Pat. No. 4,440,565, there are data showing the use of treespecific sulfonylurea compounds as abscission agents for oranges, butthe subject compounds are used in amounts exceeding the criteria for theuseable compounds of this invention and, furthermore, the compoundsdisclosed in said patent are structurally distinct from the compoundsuseable in this invention.

This invention provides a method of aiding in the harvesting of fruit,particularly olives and citrus fruits such as oranges, lemons andgrapefruit, wherein abscission is induced by application to thefruit-bearing plant an effective amount of a sulfonylurea compound or animidazolinone compound.

The imidazolinone compounds useable in the practice of this inventionare2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-arylcarboxylatesof the general formula ##STR1## wherein R is quinolin-3-COOR¹, R²-benzene-COOR¹ or 5-R³ -pyridine-3-COOR¹, in which R¹ is selected fromthe group consisting of hydrogen, methyl, ammonium and lower (i.e., C₁-C₄) alkylamine, R² is methyl in the 4- or 5-position, and R³ isselected from the group consisting of hydrogen, methyl, ethyl ormethoxymethyl.

The sulfonylurea compounds useable in the practice of this inventionfall into two general classes, namely the N-triazinylsulfonylureas andthe N-pyrimidinylsulfonylureas.

The N-triazinylsulfonylureas have the general formula ##STR2## wherein Ris hydrogen or methyl, Q is 4 methoxy-6-methyltriazin-2-yl or 4,6dimethoxytriazin-2-yl and W is 2-methoxycarbonylthiophen-3,2-(2-methoxyethoxy)phenyl, 2-(3,3,3-trifluoropropyl)phenyl,2-(2-chloroethoxy)phenyl, 2 chlorophenyl or 2-methoxycarbonylphenyl, orwherein Q is 4 ethoxy-6-methylaminotriazin-2-yl or4-dimethylamino-6-(2,2,2-trifluoroethoxy)triazin-2-yl and W is2-methoxycarbonylphenyl or 2-methoxycarbonyl-6-methylphenyl.

The N-pyrimidinylsulfonylureas have the general formula ##STR3## whereinR₄ is chloro, methyl, methoxy or difluoromethoxy, R₅ is methyl, methoxyor difluoromethoxy, and Y is 3-dimethylaminocarbonylpyridin-2-yl,4-methoxycarbonyl-3-chloro-1-methyl-1H-pyrazole-5-yl,1-methyl-4-(2-methyl-2H-tetrazol 5 yl)pyrazole-5-yl,2-cyclopropylcarbonylphenylamino, 2-ethoxycarbonylphenyl,2-methoxycarbonylphenyl, 2-(3-oxetanyloxy)carbonylphenyl,2-methoxycarbonylphenylmethyl,2-ethylsulfonylimidazo[1,2-a]pyridin-3-yl, 3-trifluoromethylpyridin2-yl, 2-chloroimidazo[1,2-a]pyridin-3-yl or1-methyl-4-hydroxycarbonylpyrazole 5 yl.

This invention also is directed to compositions for inducing abscissionof fruit which comprises one or more of the aforementioned imidazolinoneand sulfonylurea compounds. Such formulations are prepared by dissolvingor mixing the active ingredient compounds with one or more carriermaterials, as is well known in the formulation art.

The plants to be treated by the methods of this invention are fruitplants in general. For example, by applying appropriate compositions ofthis invention to citrus, olive, coffee, grape, apple, pepper, tomato,almonds, pecans, walnuts, etc., the harvest of fruits of these plantsmay be facilitated. Particular plants to be treated include citrus suchas oranges, lemons, limes and grapefruit, and olives. Oranges, becauseof their economic importance, are a most particular target crop fortreatment. The compounds of this invention cause fruit deteriorationthat is only about 5 to 12% as rapid as that caused by glyoxime (Wilcox,U.S. Pat. No. 4,052,194) or 5-chloro-3-methyl-4-nitropyrazole (Crovetti,U.S. Pat. No. 3,869,274).

Imidazolinones which are useful in the methods of this invention aredisclosed in the following three U.S. patents, all of which are herebyincorporated by reference:

1. In U.S. Pat. No. 4,798,619, Example 42, columns 103-104 andpreceding, is described the synthesis of2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylicacid, which has the common name imazaquin; in this same patent inExample 18, columns 79-80, are described the syntheses of2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-ethyl-3-pyridinecarboxylicacid, which has the common name imazethapyr, and also of±-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-pyridinecarboxylicacid which has the common name imazameth; and in Example 10, columns70-71, is described the synthesis of±-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidzaol-2-yl]-3-pyridinecarboxylicacid, which has the common name imazapyr.

2. In U.S. Pat. No. 4,188,487, columns 3-5, is described the synthesisof±-2-[4,5-dihydro-4-methyl-4-(1-methylethyl-5-oxo-1H-imidazol-2-yl]-4(and5)-methylbenzoic acid (3:2) which has the common name imazamethabenz; inthe same patent in Example 2, columns 8-10, is described the synthesisof the methyl ester of imazamethabenz.

3. In U.S. Pat. No. 5,334,576, columns 6-9, is described the synthesisof+-5-methoxymethyl-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-pyridinecarboxylicacid, which has the common name imazamox.

These imidazolinones described in the above three patents areparticularly effective in cool weather, and are extremely useful in themethods of this invention. The gentle, slow abscission activity at verylow application rates and the very minimal damage to the released fruitin methods using these imidazolinones are particularly desirable.

Sulfonylureas which are useful in the methods of this invention aredisclosed in the following 16 U.S. patents, all of which are herebyincorporated by reference:

1. In U.S. Pat. No. 4,671,819, Example H3, column 12, is described thesynthesis of1-(4-methoxy-6-methyltriazin-2yl)-3-[2-(3,3,3-trifluoropropyl)-phenylsulfonyl]-urea,which has the common name prosulfuron.

2. In U.S. Pat. No. 4,514,212, Example 2c, columns 9-10, is describedthe synthesis of[2-(2-chloroethoxy)-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]-benzenesulfonamide,which has the common name triasulfuron; synthetic methods in this samepatent may be used for the preparation of3-(4,6-dimethoxy-1,3,5-triazin-2-yl)-1-[2-(2-methoxyethoxy)-phenylsulfonyl]urea,which has the common name cinosulfuron.

3. In U.S. Pat. No. 4,478,635, Example 2c, column 10, is described thesynthesis of methyl2-[[[[[(4,6-bis(difluoromethoxy)-2-pyrimidinyl]amino]carbonyl]amino]sulfonyl]-benzoate,which has the common name primisulfuron.

4. In U.S. Pat. No. 4,394,506, Example 3, column 21, is described thesynthesis ofmethyl-2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-benzoate,which has the common name sulfometuron.

5. In U.S. Pat. No. 4,547,215, Example 2, column 3, is described thesynthesis of ethyl2-[[[[(4-chloro-6-methoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-benzoate,which has the common name chlorimuron.

6. In U.S. Pat. No. 5,209,771, columns 3 and 4, is described thesynthesis of2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-benzoicacid, 3-oxetanyl ester, which has the common name oxasulfuron.

7. In U.S. Pat. No. 4,383,113, Example 13, columns 44-45, is describedthe synthesis of methyl2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]-benzoate,which has the common name metsulfuron.

8. In U.S. Pat. No. 4,548,638, Example 1, column 4, is described thesynthesis of methyl2-[[[[[(4-ethoxy-6-(methylamino)-1,3,5-triazin-2-yl]amino]carbonyl]amino]sulfonyl]-benzoate,which has the common name ethametsulfuron.

9. In U.S. Pat. No. 4,740,234, Example 1, column 2, is described thesynthesis of methyl2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)methylamino]carbonyl]amino]sulfonyl]-benzoate,which has the common name tribenuron.

10. In U.S. Pat. No. 4,789,393, Example 9, columns 11-12, is describedthe synthesis of2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-N,N-dimethyl-3-pyridinecarboxamide,which has the common name nicosulfuron; in this same patent are methodsthat may be used to synthesize1-(4,6-dimethoxypyrimidin-2-yl)-3-[3-(trifluoromethyl)-2-pyridylsulfonyl]-urea,which has the common name flazasulfuron; and also to synthesize2-chloro-N[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]imidazo(1,2-a)pyridine-3-sulfonamide,which has the common name imazosulfuron.

11. In U.S. Pat. No. 4,127,405, Example 3, column 8, is described thesynthesis of2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]-benzenesulfonamide,which has the common name chlorsulfuron.

12. In U.S. Pat. No. 4,420,325, Examples 14-16, columns 13-16, isdescribed the synthesis of methyl 2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]aminosulfonyl]methyl]-benzoate, which has the common namebensulfuron.

13. In U.S. Pat. No. 5,090,933, Example 6, column 9, is described thesynthesis of methyl2-[[[[[(4-(dimethylamino)-6-(2,2,2-trifluoroethoxy)-1,3,5-triazin-2-yl]amino]carbonyl]amino]sulfonyl]-3-methylbenzoate,which has the common name triflusulfuron.

14. In U.S. Pat. No. 5,492,884, column 2, is described the synthesis of[[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]amino]-2-(cyclopropylcarbonyl)-benzene,which has the common name cyclosulfamuron.

15. in U.S. Pat. No. 4,746,353, columns 14-20, is described thesynthesis ofN-[[(4,6-dimethoxy-2-pyrimidinyl)-amino]carbonyl]-1-methyl-4-(2-methyl-2H-tetrazol-5-yl)]-1H-pyrazole-5-sulfonamide,which has the common name azimsulfuron.

16. In U.S. Pat. No. 4,668,277, Example 2, columns 5-6, is described thesynthesis of methyl 5-[[(4,6-dimethoxy-2-pyrimidinyl)-aminocarbonylaminosulfonyl]-3-chloro-1-methyl]-1-H-pyrazole-4-carboxylate,which has the common name halosulfuron; in this same patent are setforth methods that may be used to synthesize5-(4,6-dimethyoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyrazole-4-carboxylicacid, which has the common name pyrazosulfuron.

17. In U.S. Pat. No. 4,481,029, Example 34, columns 34-35, is describedthe synthesis of methyl3-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]-2-thiophenecarboxylate,which has the common name thifensulfuron.

18. In U.S. Pat. No. 5,017,212, columns 29-40, is described thesynthesis ofN-(2-ethylsulfonylimidazo[1,2-a]pyridin-3-ylsulfonyl)-N'-(4,6-dimethoxy-2-pyrimidinyl)urea,which has the common name sulfosulfuron.

These sulfonylureas described in the above 16 patents are extremelyuseful in the methods of this invention. The gentle, slow abscissionactivity at very low application rates and the very minimal damage tothe released fruit in methods using these imidazolinones areparticularly desirable.

The active substances of this invention are not phytotoxic in the usualapplication concentrations, and they have low toxicity towardswarm-blooded animals. Moreover, they produce no morphological changes ofthe plants and cause no damage to them. They promote, in particular, thedevelopment of abscission layers. Consequently, fruits of all kinds,e.g., stone fruit (e.g., cherries), berries, pomaceous fruit (e.g.,apples) or oil fruits (e.g., olives), nuts, and particularly citrusfruits, can be separated from the plants, manually or mechanically,without any great amount of force being applied. Damage to foliage,branches, or fruit, which normally occurs when fruit is removed by theshaking of trees and shrubs, or by the plucking of the fruit from thebranches, is largely avoided, and the production capacity of the treesis thus increased.

The extent and nature of the action are governed by the most diversefactors, depending on the type of plant, and particularly on the appliedconcentration and on the time of application with regard to the stage ofdevelopment of the plant and the fruit. Thus, for example, plants ofwhich the fruits is to be sold, or in some other way utilized, aretreated immediately after blossoming or at an appropriate length of timebefore the gathering of the fruit. The active substances are appliedpreferably in the form of liquid preparations, these being applied toparts of plants above the soil, to the surface of the soil or into thesoil. Application to parts of plants above the soil is preferred, forwhich purpose solutions or aqueous dispersions are most suitable.

The active substances of this invention may be used together withsuitable carriers, solvents and/or other additives, or in many cases asformulated by the manufacturer. A preferred adjuvant is Silwet L-77, anon-ionic adjuvant, a silicon-polyether copolymer distributed byLoveland Industries, Inc., but one skilled in the art can substituteother adjuvants with acceptable results. Suitable carriers and additivescan be solid or liquid, and correspond to the substances normally usedin formulation practice, for example, solvents, diluents, dispersingagents, wetting agents, other surfactants, adhesives and thickening orbonding agents. Most conveniently, the formulations will be prepared inconcentrated form to which water can be added to produce the solutionsand slurries described above. As used herein, the term "carrier" refersto all of the solvents diluents, surfactants, etc., comprising thesubject formulations, other than the active imidazolinone orsulfonylurea ingredient.

The applied amounts are largely governed by the purpose and nature ofthe application (treatment of the soil or of parts of plants). The usualconcentrations applied to above-ground parts of fruit crops are betweenabout 15 ppm and about 200 ppm, in aqueous solution or slurry, toincipient run-off. It is preferable, for environmental and otherreasons, to use the subject compounds in as low concentrations aspossible. Therefore, it is preferable to employ concentrations below 100ppm if possible and more preferable to employ concentrations below 60ppm. These application rates are unusually low, and thereforeenvironmentally desirable as they produce less burden of extraneouscompounds in the environment. It has been found that suitableapplication rates for the sulfonylureas are from 20 to 50 ppm, with arate of about 30 ppm being especially preferred. For the imidazolinones,the preferred rates are somewhat higher, namely in the range of 40 to 70ppm, with a rate of about 50 ppm being especially preferred. The optimumtime of application to promote fruit abscission is shortly beforeharvesting, i.e., about 3 days to 4 weeks before harvesting. In typicalorange groves, the aqueous solution or slurry is applied at a rate ofabout 46 to 460 liters per hectare (30-300 gallons per acre).

EXAMPLES

In the following examples, abscission agents are applied at low pressureto the point of incipient run-off to branches carrying a counted numberof fruit or to whole fruit trees. Concentrations are expressed in partsof active ingredient per million parts of carrier (ppm). Silwet L-77 wasadded to carrier and control water at 2 ml per gallon (3.8 liters).Other adjuvants used in addition in some examples were foliarfertilizers: urea; triazone, N/P₂ O₅ /K₂ O=28-0-0 and KP3, potassiumphosphonate, N/P₂ O₅ K₂ O=0-22-20. At a specified number of days aftertreatment (DAT), the pull force (PF) (in lb) needed to remove the fruitas measured by means of a Hunter Force Gauge is recorded. Fallen maturefruit is recorded as 0 lb (0 Kg), or in some cases recorded as % MFD (%Mature Fruit Drop). Fruit that is too loose to deflect the Hunter ForceGauge is recorded as 0 lb (0 Kg), or in some cases recorded as % TLP (%Too Loose to Pull). Young fruit drop is recorded as % YFD and leaf dropas % LD where either is present. Cultivars where completely known arereported as "Scion/stock", as in "Valencia/sour orange", or otherwisewhere only the scion is known "Valencia".

Example 1

Sulfometuron and three other compounds are applied to "Valencia/sourorange" cultivar in a replicated branch test to determine citrusabscission activity. All materials are applied at 30 ppm to 10 fruit perbranch in each of three replicates at an ambient temperature of 16° C.(60° F.) in Orange County, Florida. Pull force determinations are made21 days after application.

    ______________________________________                                                             Pull Force                                               Treatment  Rate Applied, ppm                                                                             lb.    Kg.                                         ______________________________________                                        Sulfometuron                                                                             30              0      0                                           Triasulfuron                                                                             30              4.2    1.9                                         Nicosulfuron                                                                             30              6.0    2.7                                         Primisulfuron                                                                            30              3.0    1.4                                         Control    --              19.1   8.7                                         ______________________________________                                    

Example 2

Abscission treatments are applied to three replications of five fruit onone branch of "Hamlin/sour orange". Pull forces are measured 15 daysafter treatment.

    ______________________________________                                                             Pull Force                                               Treatment  Rate Applied, ppm                                                                             lb.    Kg.                                         ______________________________________                                        Sulfometuron                                                                              30             1.0    0.5                                         Sulfometuron                                                                              90             0.     0                                           Glyoxime   600             4.5    2.0                                         Control    --              16.5   7.5                                         ______________________________________                                    

Example 3

Sulfometuron and hexazinone are compared at 30 and 90 ppm. Alltreatments are applied to three branches of 10 fruit each assigned incompletely randomized design to "Valencia" oranges. Results are notedtwo weeks after treatment.

    ______________________________________                                        Treatment  Rate Applied, ppm                                                                            % MFD   % YFD                                       ______________________________________                                        Sulfometuron                                                                             30             74.2    0                                           Sulfometuron                                                                             90             84.6    0                                           Hexazinone 30             0       0                                           Hexazinone 90             0       10                                          Control    --             0       0                                           ______________________________________                                    

Example 4

Sulfometuron at 90 ppm is compared to glyoxime at 600 ppm on "Hamlin"oranges at an ambient temperature of 11° C. (52° F.). Single branches of10 fruit each are used in each of three replications in a completelyrandomized design. Results are noted 15 days after treatment.

    ______________________________________                                                             Pull Force                                               Treatment  Rate Applied, ppm                                                                             lb.    Kg.                                         ______________________________________                                        Sulfometuron                                                                              90             1.6    0.7                                         Glyoxime   600             7.3    3.3                                         Control    --              18.1   8.2                                         ______________________________________                                    

Example 5

Sulfometuron, metsulfuron, and chlorsulfuron, all at 30 ppm, arecompared to phosphorous acid, hypophosphorous acid, dibutylurea, andglyoxime, all at 600 ppm on "Hamlin" oranges. Pull force for fruitremoval is measured after three weeks as an average of three replicatedbranches (five fruit) assigned in a completely randomized design.

    ______________________________________                                                               Pull Force                                             Treatment     Rate Applied, ppm                                                                            lb.    Kg.                                       ______________________________________                                        Sulfometuron   30            1.9    0.9                                       Metsulfuron    30            7.2    3.3                                       Chlorsulfuron  30            7.4    3.4                                       Hypophosphorous acid                                                                        600            17.1   7.7                                       Phosphorous acid                                                                            600            16.6   7.5                                       Dibutylurea   600            12.7   5.8                                       Glyoxime      600            3.3    1.5                                       Control       --             17.8   8.1                                       ______________________________________                                    

Example 6

Abscission treatments are applied to a single four-year-old whole treesof "Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree eight days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Imazameth                                                                              90            0       0.5   11.2 5.1                                 Imazameth                                                                              90                                                                   + 2% KP3               65      1.0   2.6  1.2                                 2% KP3                 0       1.0   18.1 8.2                                 Control  --            0       0.5   20.2 9.2                                 ______________________________________                                    

Example 7

Abscission treatments are applied to single four-year-old trees of"Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree 14 days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Imazameth                                                                              90            87      1.0   0    0                                   Imazameth                                                                              90                                                                   + 2% KP3               94      1.0   0    0                                   2% KP3                 0       1.0   19.6 8.9                                 Control  --            0       0.5   21.0 9.5                                 ______________________________________                                    

Example 8

Abscission treatments are applied to single four-year-old whole trees of"Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree nine days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Sulfometuron                                                                           30            65      0.5   4.2  1.9                                 Sulfometuron                                                                           30                                                                   + 2% KP3               90      1.0   0    0                                   2% KP3                 0       1.0   19.6 8.9                                 Control  --            0       0.5   21.0 9.5                                 ______________________________________                                    

Example 9

Abscission treatments are applied to single four-year-old whole trees of"Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree 15 days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Sulfometuron                                                                           23            72.0    0.5   4.6  2.1                                 Sulfometuron                                                                           23                                                                   + 2% KP3               86.0    0.5   0    0                                   2% KP3                 0       0.5   20.9 9.5                                 Control  --            0       0.5   19.6 8.9                                 ______________________________________                                    

Example 10

Abscission treatments are applied to single four-year-old whole trees of"Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree 19 days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Sulfometuron                                                                           23            85      0     --   --                                  Sulfometuron                                                                           23                                                                   + 2% Triazone          95      0.5   --   --                                  Imazameth                                                                              60                                                                   Imazameth                                                                              60                                                                   + 2% Triazone          95      0     --   --                                  Control  --            0       0     20.6 9.4                                 ______________________________________                                    

Example 11

Abscission treatments are applied to single four-year-old whole trees of"Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree 13 days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Imazameth                                                                              70            50      0     --   --                                  Imazameth                                                                              70                                                                   + 2% Urea              75      0.5   --   --                                  Sulfometuron                                                                           23            30      0.5   --   --                                  Sulfometuron                                                                           23                                                                   + 2% Urea              95      10    --   --                                  Control  --            0       0     19.8 9.0                                 ______________________________________                                    

Example 12

Abscission treatments are applied to single whole trees of"Hamlin/Carrizo" on January 3. Temperatures fall to about -4° C.(mid-20° F.) on January 7, 8 and 9. Pull forces and other data arerecorded 21 days after treatment on January 24.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Prosulfuron                                                                            30            55      1     --   --                                  Prosulfuron                                                                            15                                                                   + Triasulfuron                                                                         15            65      2     --   --                                  Primisulfuron                                                                          30            40      2     --   --                                  Oxasulfuron                                                                            30            55      2     --   --                                  Control  --            0       2     15.6 7.1                                 ______________________________________                                    

Example 13

Abscission treatments are applied to single four-year-old whole trees of"Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree 15 days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Prosulfuron                                                                            30            80      0     --   --                                  Triasulfuron                                                                           30            90      1     --   --                                  Primisulfuron                                                                          30            40      0     --   --                                  Oxasulfuron                                                                            30            95      0     --   --                                  Control  --            0       0     19.4 8.8                                 ______________________________________                                    

Example 14

Abscission treatments are applied to single four-year-old whole trees of"Parson Brown/Carizzo". Pull forces and other data are recorded on 10oranges per tree 13 days after treatment.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Imazameth                                                                              70            80      0     --   --                                  Imazameth                                                                              70                                                                   + 1% Triazone          90      0     --   --                                  Control  --            0       0     20.4 9.3                                 ______________________________________                                    

Example 15

Abscission treatments are applied to four branches (i.e., fourreplications) of "Hamlin" orange. Pull forces and other data arerecorded on 10 oranges per replication 21 days after treatment.

    ______________________________________                                                             Pull Force                                               Treatment Rate Applied, ppm                                                                              lb.    Kg.                                         ______________________________________                                        Imazapyr  45               8.1    3.7                                         Imazameth 45               4.5    2.0                                         Imazethapyr                                                                             45               7.3    3.3                                         Control   --               12.5   5.7                                         ______________________________________                                    

Example 16

Abscission treatments are applied to four branches (i.e., fourreplications) of "Hamlin" orange. Pull forces are recorded on 10 orangesper replication 21 days after treatment.

    ______________________________________                                                             Pull Force                                               Treatment Rate Applied, ppm                                                                              lb.    Kg.                                         ______________________________________                                        Imazaquin 135              4.3    2.0                                         Imazapyr  135              1.1    0.5                                         Imazethapyr                                                                             135              0.2    0.1                                         Sulfometuron                                                                             90              1.0    0.5                                         Control   --               17.1   7.7                                         ______________________________________                                    

Example 17

Abscission treatments are applied to four branches (i.e., fourreplications) of "Hamlin" orange. Pull forces are recorded on 10 orangesper replication 15 days after treatment.

    ______________________________________                                                             Pull Force                                               Treatment Rate Applied, ppm                                                                              lb.    Kg.                                         ______________________________________                                        Imazapyr  135              3.3    1.5                                         Imazameth  45              0.8    0.4                                         Imazameth  90              0.0    0.0                                         Imazameth 135              0.2    0.1                                         Glyoxime  600              2.5    1.1                                         Control   --               16.6   7.5                                         ______________________________________                                    

Example 18

Abscission treatments are applied to three branches (i.e., threereplications) of "Valencia" orange. Pull forces are recorded on 10oranges per replication 30 days after treatment.

    ______________________________________                                                             Pull Force                                               Treatment Rate Applied, ppm                                                                              lb.    Kg.                                         ______________________________________                                        Imazameth 45               4.3    2.0                                         Imazameth 60               1.4    0.6                                         Imazameth 90               0.0    0.1                                         Imazameth 135              1.1    0.5                                         Sulfometuron                                                                            90               1.5    0.7                                         Control   --               22.7   10.3                                        ______________________________________                                    

Example 19

Abscission treatments are applied to three branches (i.e., threereplications) of "Hamlin" orange. Pull forces are recorded on 10 orangesper replication 21 days after treatment.

    ______________________________________                                                             Pull Force                                               Treatment Rate Applied, ppm                                                                              lb.    Kg.                                         ______________________________________                                        Imazameth  60              2.1    1.0                                         Sulfometuron                                                                             30              1.7    0.8                                         Phosphorous Acid                                                                        600              17.8   8.1                                         Dibutylurea                                                                             600              16.9   7.7                                         Glyoxime  600              18.1   8.2                                         Control   --               19.2   8.7                                         ______________________________________                                    

Example 20

Abscission treatments are applied to four branches (i.e., fourreplications) of "Valencia" orange. Pull forces are recorded on 10oranges per replication 14 days after treatment.

    ______________________________________                                                             Pull Force                                               Treatment Rate Applied, ppm                                                                              lb.    Kg.                                         ______________________________________                                        Imazapyr  90               1.5    0.7                                         Imazameth 90               1.4    0.6                                         Imazethapyr                                                                             90               6.1    2.8                                         Imazaquin 90               6.0    2.7                                         Imazamox  90               6.6    3.0                                         Imazamethabenz                                                                          90               7.7    3.5                                         Control   --               23.8   10.9                                        ______________________________________                                    

Example 21

Abscission treatments are applied to single whole trees of"Hamlin/Carizzo" on January 3. Temperatures fall to about -4° C.(mid-20° F.) on January 1, 8 and 9. Pull forces and other data arerecorded from 10 fruit 21 days after treatment on January 24.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Prosulfuron                                                                            15                                                                   + Triasulfuron                                                                         15            65      2     --   --                                  Primisulfuron                                                                          30            40      2     --   --                                  Oxasulfuron                                                                            30            55      2     --   --                                  Control  --            0       2     15.6 7.1                                 ______________________________________                                    

Example 22

Abscission treatments are applied to single whole trees of"Hamlin/Carizzo". Pull forces and other data are recorded from 10 fruitseven DAT and 14 DAT.

    __________________________________________________________________________                     7 DAT      14 DAT                                            Treatment                                                                            Rate Applied, ppm                                                                       % MFD                                                                             % LD                                                                              PF % MFD                                                                             % LD                                                                              LF                                        __________________________________________________________________________    Prosulfuron                                                                          30        10  2      80  2                                             Triasulfuron                                                                         30        55  2      90  2                                             Primisulfuron                                                                        30        80  2      95  2                                             Oxasulfuron                                                                          30        65  2      90  2                                             Control                                                                              --        0   2   15.6       14.0                                      __________________________________________________________________________

Example 23

Abscission treatments are applied to single whole trees of "ParsonBrown/Cleo" on January 3. Temperatures fall to about -4° C. (mid-20° F.)on January 1, 8 and 9. Pull forces and other data are recorded from 10fruit 21 days after treatment on January 24.

    ______________________________________                                                                 Pull Force                                           Treatment                                                                              Rate Applied, ppm                                                                           % MFD   % LD  lb.  Kg.                                 ______________________________________                                        Prosulfuron                                                                            30            55      1     --   --                                  Prosulfuron                                                                            30                                                                   + 1% KP3               65      1     --   --                                  1% KP3                 0       2     15.0 6.8                                 Control  --            0       1     17.2 7.8                                 ______________________________________                                    

Example 24

Abscission treatments are applied to three branches (i.e., threereplications) of "Hamlin" orange. Observations are recorded on 10oranges per replication 21 days after treatment.

    ______________________________________                                                               Pull Force                                             Treatment                                                                              Rate Applied, ppm                                                                           % MFD     lb.  Kg.                                     ______________________________________                                        Halosulfuron                                                                           31            0         11.5 5.2                                     Chlorsulfuron                                                                          31            50        --   --                                      Tribenuron                                                                             31            55        --   --                                      Metsulfuron                                                                            31            60        --   --                                      Sulfometuron                                                                           31            65        --   --                                      Imazaquin                                                                              64            55        --   --                                      Imazethapyr                                                                            64            55        --   --                                      Control  --            0         12.5 5.7                                     ______________________________________                                    

Example 25

Applying the following abscission treatments as described in Example 24should result in the great majority of treated fruit being too loose topull 21 days after treatment, with untreated fruit tightly adherent.

    ______________________________________                                        Treatment     Rate Applied, ppm                                               ______________________________________                                        Triflusulfuron                                                                              30                                                              Ethametsulfuron                                                                             30                                                              Azimsulfuron  30                                                              Bensulfuron   30                                                              Cyclosulfamuron                                                                             30                                                              ______________________________________                                    

Example 26

Applying the following abscission treatments to olives or pecans,otherwise as described in Example 24 should result in the great majorityof treated fruit falling to the ground within 21 days after treatment,with untreated fruit tightly adherent.

    ______________________________________                                        Treatment     Rate Applied, ppm                                               ______________________________________                                        Prosulfuron   40                                                              Triasulfuron  40                                                              Primisulfuron 40                                                              Oxasulfuron   40                                                              Sulfometuron  40                                                              Imazameth     80                                                              Imazapyr      80                                                              ______________________________________                                    

Example 27

Applying the following abscission treatments as described in Example 24should result in the great majority of treated fruit being too loose topull 21 days after treatment, with untreated fruit tightly adherent.

    ______________________________________                                        Treatment     Rate Applied, ppm                                               ______________________________________                                        Cinosulfuron  30                                                              Imazosulfuron 30                                                              Pyrazosulfuron                                                                              30                                                              Sulfosulfuron 30                                                              Flazasulfuron 50                                                              Imazamox      50                                                              Cyclosulfamuron                                                                             30                                                              ______________________________________                                    

Example 28

Commercially formulated prosulfuron of 57% concentration is diluted to30 ppm in water containing 2 ml Silwet per gallon (3.8 liters), and theresultant solution applied to the point of incipient run-off to entiremature "Valencia/sour orange" trees. Ten days later, 95% of the fruithave pull force of less than 4 lbs. (1.8 kg.). Twenty-one days aftertreatment, 97% of the fruit are on the ground. Forty days aftertreatment, the fallen fruit are still in good condition on the ground.

We claim:
 1. A method of aiding in the harvesting of fruit whichcomprises inducing abscission of said fruit by applying to afruit-bearing plant an effective amount of a2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-arylcarboxylatecompound of the formula ##STR4## wherein R is quinolin-3-COOR₁, R₂-benzene-COOR₁ or 5-R₃ -pyridine-3-COOR₁, in which R₁ is selected fromthe group consisting of hydrogen, methyl, ammonium and C₁ -C₄alkylamine, R₂ is methyl in the 4- or 5-position, and R₃ is selectedfrom the group consisting of hydrogen, methyl, ethyl or methoxymethyl.2. A method according to claim 1 in which the compound is dissolved ordispersed in water at a concentration of from about 15 to about 200 ppmand the aqueous solution or slurry is applied to the fruit-bearing areasof the plant to the point of incipient run-off.
 3. A method according toclaim 2 in which the compound is dissolved or dispersed in water of aconcentration of from 40 to 70 ppm.
 4. A method according to claim 3 inwhich the compound is dissolved or dispersed in water at a concentrationof about 50 ppm.
 5. A method according to claim 3 in which the compoundis imazaquin or a salt thereof.
 6. A method according to claim 3 inwhich the compound is imazethapyr or a salt thereof.
 7. A methodaccording to claim 4 in which the compound is imazapyr or a saltthereof.
 8. A method according to claim 4 in which the compound isimazameth or a salt thereof.
 9. A method according to claim 2 in whichthe compound is imazamox or a salt thereof.
 10. A method according toclaim 2 in which the compound is imazamethabenz or a slat or the methylester thereof.
 11. The method of claim 2 in which the fruit is olives ora citrus fruit.
 12. The method of claim 11 in which the fruit is acitrus fruit.
 13. A method of aiding in the harvesting of fruit whichcomprises inducing abscission of said fruit by applying to thefruit-bearing plant an effective amount of a sulfonylurea compound ofthe formula ##STR5## wherein Q is 4-methoxy-6-methyltriazin-2-yl or 4,6dimethoxytriazin-2 yl, R is hydrogen or methyl and W is2-methoxycarbonylthiophen-3, 2-(2 methoxyethoxy)phenyl,2-(3,3,3-trifluoropropyl)phenyl, 2-(2-chloroethoxy)phenyl,2-chlorophenyl or 2-methoxycarbonylphenyl, or wherein Q is4-ethoxy-6-methylaminotriazin-2-yl or 4-dimethyl amino-6(2,2,2-trifluoroethoxy)triazin-2-yl, R is hydrogen and W is2-methoxycarbonylphenyl or 2-methoxycarbonyl-6-methylphenyl.
 14. Amethod according to claim 13 in which the compound is dissolved ordispersed in water at a concentration of from about 15 to about 200 ppmand the aqueous solution or slurry is applied to the fruit-bearing areasof the plant to the point of incipient run-off.
 15. A method accordingto claim 14 in which the compound is dissolved or dispersed in water ata concentration of from 20 to 50 ppm.
 16. A method according to claim 15in which the compound is dissolved or dispersed in water at aconcentration of about 30 ppm.
 17. A method according to claim 15 inwhich the compound is prosulfuron.
 18. A method according to claim 15 inwhich the compound is triasulfuron.
 19. A method according to claim 13in which the compound is metsulfuron.
 20. A method according to claim 14in which the compound is chlorsulfuron.
 21. A method according to claim14 in which the compound is tribenuron.
 22. A method according to claim14 in which the compound is triflusulfuron.
 23. A method according toclaim 14 in which the compound is ethametsulfuron.
 24. A methodaccording to claim 15 in which the compound is thifensulfuron.
 25. Themethod of claim 14 in which the fruit is olives or a citrus fruit. 26.The method of claim 25 in which the fruit is a citrus fruit.
 27. Amethod of aiding in the harvesting of fruit which comprises inducingabscission of said fruit by applying to the fruit-bearing plant aneffective amount of a sulfonylurea compound of the formula ##STR6##wherein R₄ is chloro, methyl, methoxy or difluoromethoxy, R₅ is methyl,methoxy or difluoromethoxy, and Y is3-dimethylaminocarbonylpyridin-2-yl,4-methoxycarbonyl-3-chloro-1-methyl-1H-pyrazole-5-yl, 1methyl-4-(2-methyl-2H-tetrazol-5-yl)-pyrazole-5-yl,2-cyclopropylcarbonylphenylamino, 2-ethoxycarbonylphenyl,2-methoxy-carbonylphenyl, 2-(3-oxetanyloxy)carbonylphenyl,2-methoxycarbonylphenylmethyl,2-ethylsulfonylimidazo[1,2-a]pyridin-3-yl,3-trifluoromethylpyridin-2-yl, 2-chloroimidazo[1,2-a]pyridin 3-yl or1-methyl-4-hydroxycarbonylpyrazole-5-yl.
 28. A method according to claim27 in which the compound is dissolved or dispersed in water at aconcentration of from about 15 to about 200 ppm and the aqueous solutionor slurry is applied to the fruit-bearing areas of the plant to thepoint of incipient run-off.
 29. A method according to claim 28 in whichthe compound is dissolved or dispersed in water of a concentration offrom 20 to 50 ppm.
 30. A method according to claim 29 in which thecompound is dissolved or dispersed in water at a concentration of about30 ppm.
 31. A method according to claim 28 in which the compound isnicosulfuron.
 32. A method according to claim 28 in which the compoundis azimsulfuron.
 33. A method according to claim 28 in which thecompound is primisulfuron.
 34. A method according to claim 28 in whichthe compound is sulfometuron.
 35. A method according to claim 28 inwhich the compound is oxasulfuron.
 36. A method according to claim 28 inwhich the compound is chlorimuron.
 37. A method according to claim 27 inwhich the compound is bensulfuron.
 38. A method according to claim 28 inwhich the compound is cyclosulfamuron.
 39. A method according to claim28 in which the compound is sulfosulfuron.
 40. A method according toclaim 27 in which the compound is halosulfuron.
 41. The method of claim28 in which the fruit is olives or a citrus fruit.
 42. The method ofclaim 41 in which the fruit is a citrus fruit.